Already publicly known is a technique of performing, using a touchpad or a touch panel, input operations for objects displayed on a screen. Changing the sizes of objects to be displayed on a screen facilitates the selection of the objects with the touchpads or the touch panels, and thus the operability of the touchpads or the touch panels can be increased by preventing wrong operations from occurring.
PTL 1 discloses, as a conventional technique, a technique of changing the sizes of objects to be displayed on a screen. The technique disclosed by PTL 1 allows an operator (user) to operate a touch panel while an object is being increased or decreased in size, detects, for the object, the minimum width X and height Y which enable the operation, and displays the object with optimum width X and height Y. Thus, the technique makes it possible to prevent the wrong operations on the touch panel from occurring.